Normally, I'd say blend in the text, but you should test it yourself and see which brings a better CTR. For example, I remember someone on a forum saying that blended ads had a horrible CTR for his site that was aimed at kids. Kids were attracted more by brightly colored ads that stood out. Test it yourself and compare
I have the ads blend in the text on all of my sites. I have a forum also (targeting womans) and the CTR is horrible no matter what. This is how forums generally are.
I usually make the links on my website a bit different color, not the same as teh text. THen I blend in the ads the same as the text. gving the title the same color as the link color I use on my page.